Continuous monitoring of muscle gas tensions and pH during tissue acid-base disturbances

To evaluate the applicability of continuous muscle P_O2 and P_CO2 monitoring as indicators of physiologic abnormalities, muscle (m) P_O2 and P_CO2 was measured by mass spectrometry and pH by muscle surface probe in the limb muscle of 16 dogs subjected to hemorrhage, acid infusion, hypoxia, or hypocarbia and hypercarbia. These values were compared to arterial (a) pH, P_O2, and P_CO2.During hemorrhage, mP_O2 fell sharply; mP_CO2 rose and mpH decreased linearly in proportion to the rate and the magnitude of the bleed. mP_O2 fell with the onset of blood loss, whereas significant mP_CO2 and mpH changes resulting from tissue acidosis were evident only after a large volume loss.Metabolic acidosis produced by acid infusion caused a parallel drop in arterial and mpH, a rise in mP_CO2, and no change in mP_O2.During progressive hypoxia, aP_O2 and mP_O2 reflected the changes in inspired O₂. MpH and apH fell only when mP_O2 fell to low levels. Hypercarbia and hypocarbia caused parallel changes in mP_CO2 which were also reflected in apH and mpH.Continuous muscle gas measurements appear feasible and combined with muscle pH monitoring should help the clinician pinpoint the cause of physiologic derangements in the critically ill.     

Experience with clinical and operative staging of Hodgkin's disease in children.

Accurate staging is critical for the proper treatment of Hodgkin's disease. In the past 5 yr, 60 children with Hodgkin's disease were staged by celiotomy which included splenectomy and biopsy of liver, retroperitoneal lymph nodes, and bone. Fifty children underwent staging celiotomy at initial diagnosis (Group I). Ten others were staged surgically because of suspected reactivation of disease diagnosed and treated before current staging methods were employed (Group II). Forty-one of 50 children in Group I had Stage I or II disease, seven Stage III, and two Stage IV. As a result of operation, therapy was altered in seven children. Three had a higher stag e and four a lower stage than that suspected by clinical evaluation, including two with liver involvement. Of the two patients in Group II, celiotomy revealed unsuspected splenic disease in seven, including one with liver involvement. Celiotomy and splenectomy were well tolerated and no long-term complications have been noted (average follow-up 2 yr). Forty-nine of 50 children in Group I and six of ten in Group II are alive without disease. No cases of sepsis attributable to splenectomy have been observed.     

The effect of helium-oxygen mixtures on body temperature

When animals breathed a mixture of cold helium-oxygen, while also exposed to it, their rectal temperature fell three times faster than when they were exposed to cold nitrogen-oxygen mixture. In further studies using a special chamber, the addition of helium to the inspired air and to the ambient air, promoted faster cooling than when helium was used in the inspired air alone or in the ambient air alone, demonstrating that helium can be used to regulate body temperature, when the gas temperature is controlled by a heat exchanger.Temperature regulation with helium may be useful for pediatric anesthesia, treatment of malignant hyperthermia, induction of hypothermia in neonatal cardiac surgery, and for resuscitation of hypothermic neonates.     

Lymphoid depletion in ileal loops: Mechanism and clinical implications

Recent long-term follow-up studies of children undergoing ileal loop urinary diversion have shown a number of complications arising in these patients: recurrent urinary tract infections, deteriorating renal function, and late midloop stricture. We suggest that all three may be related to the same underlying problem, namely, a severe depletion of lymphoid elements in the intestine.In both clinical and animal studies urine exposure to intestinal segments resulted in a marked depletion of lymphoid elements from the Peyer's patches and from beneath the intestinal villi in the intestine. In addition there was an associated hypertrophy of the lymph nodes in the ileal loop mesentery. When the intestine was no longer exposed to urine, there was a prompt regeneration and reappearance of the lymphoid elements. The lymphocytes seemed to “home in” on the submucosal areas and reform Peyer's patches once the urine was removed. The hyperplastic lymph nodes in the ileal loop mesentery regressed when urine exposure was removed.Conventional treatment of ileal loop infections focuses on the upper urinary tracts. Mid-loop stenoses are treated by resection and creation of a new ileal loop conduit. Local therapy in the form of antibiotics and/or steroid enemas may relieve some late midloop obstruction and prevent further damage to renal parenchyma.     

Subclavian Arterioplasty for the Ipsilateral Blalock-Taussig Shunt

A Blalock-Taussig shunt on the side of the aortic arch (ipsilateral) may result in kinking of the subclavian artery as it passes over the aortic arch. A technique is described to avoid this problem. A subclavian arterioplasty is performed which brings the orifice of the subclavian artery more anteriorly on the aortic arch and enlarges its orifice.     

Transposition of the great arteries and intact ventricular septum: anatomical repair in the neonate

Fourteen neonates 18 hours to 32 days old with transposition of the great arteries (TGA) and virtually intact ventricular septum (IVS) underwent arterial switch operations under deep hypothermic circulatory arrest. Preoperative left ventricular to right ventricular peak systolic pressure ratios ranged from 0.7 to 1.0 (mean, 0.92), and the echocardiogram showed a centrally positioned ventricular septum in 10 patients and a rightward displaced ventricular septum in 4. One patient died twelve hours after operation. Postoperative complications included bleeding from the left coronary artery-pulmonary artery anastomosis (1 patient), stenosis of the pulmonary artery-aorta anastomosis requiring reoperation (2 patients), transient ST segment and T wave abnormalities consistent with ischemia (3), and development of pathological Q waves suggestive of clinically silent infarction (2). The capacity of the left ventricle in a neonate to effectively take over the systemic circulation was clearly demonstrated. A longer follow-up period is needed to assess late ventricular function, coronary ostial growth, growth of the aorta-pulmonary artery anastomosis, late aortic valve (anatomical pulmonary valve) function before definitive recommendations about the superiority of the arterial switch operation in neonates with TGA plus IVS can be formulated.     

Amino acid utilization during total parenteral nutrition in the surgical neonate

Amino acids, urea nitrogen, and creatinine in plasma and urine, and total urinary nitrogen were determined in five neonates during prolonged parenteral feeding. A fibrin hydrolysate-dextrose or a crystalline amino acid-dextrose solution was infused for periods as long as 33 days. These solutions supplied essential amino acids and total nitrogen (mostly as glycine) in excess of that available to infants on oral diets.Despite weight gain, positive nitrogen balance, and the absence of excessive amino aciduria, several biochemical abnormalities were detected. Plasma lysine, leucine, and glycine were consistently elevated and in one low birth weight infant, plasma phenylalanine and valine were also markedly raised. The excessive supply of glycine and nitrogen resulted in elevated urea levels in the blood and urine.The capacity to transform phenylalanine to tyrosine and methionine to cystine required by infants fed the tyrosine-cystine-free crystalline amino acid solution may be deficient in low birth weight premature infants and others with impaired liver function.These findings suggest that a more precise tailoring of the amino acid content of infusates for parenteral feeding is indicated. Such individually tailored solutions would decrease the metabolic and excretory load on the liver and kidneys.     

Exercise tolerance after repair of tetralogy of Fallot.

Twelve patients who had undergone complete repair of tetralogy of Fallot at ages ranging from 8 to 27 years were studied for exercise tolerance several years later. Work performance ranged from 58 to 130% of that predicted. Increased physiological dead space and alveolar-arterial Po2 difference at exercise suggested pulmonary vascular disease, which was confirmed in 1 patient by pulmonary angiography. Excercise tolerance decreased with increasing age at time of repair, underlining the desirability of early corrective operation.     

Local cardiac hypothermia for myocardial protection during correction of congenital heart disease.

Eighty-eight operations for correction of intracardiac congenital heart defects were performed using local cardiac hypothermia for protection of the ischemic myocardium. Twenty-six patients underwent repair of tetralogy of Fallot, 23 had patch closure of ventricular septal defect, 24 had correction of various types of congenital aortic stenosis, and 15 were operated upon for other complex lesions. The overall operative mortality was 5.6%. Ischemia times ranged from 9 to 119 minutes (mean, 48 minutes). Ischemic arrest protected by local cardiac hypothermia provides an optimal operative field, permitting repair of uncomplicated intracardiac defects in a precise, unhurried manner. No hemodynamic abnormalities attributable to the technique were encountered.     

The use of demineralized xenogeneic bone implants to correct phalangeal defects: a case report

Demineralized bovine bone blocks and powder were used to reconstruct phalangeal defects created by excision of bulging endochondromas . Bony reconstruction was documented by roentgenography at 9 weeks and by biopsy at 7 months. Follow-up at 22 months has shown stability of the implants, further ossification, and no recurrence of the phalangeal endochondromas . The use of xenogeneic demineralized bone implants promotes induced osteogenesis and rapid healing, avoids harvesting procedures, and offers a potentially unlimited supply of banked material.     

Pulmonary hypertension and congenital heart disease

Pulmonary hypertension occurs in patients with congenital heart disease and may be caused by increased volume of pulmonary blood flow or by anatomical changes in the pulmonary vasculature. Therefore, the determination of pulmonary vascular resistance expresses the status of the pulmonary vascular bed more accurately than does the level of the pulmonary artery pressure alone. Knowledge of the anatomical changes in pulmonary vessels is important in assessing surgical indications and operative risks.     

Experience with valved conduits for repair of congenital cardiac lesions.

Dacron valved conduits or aortic allografts were placed between the right heart and the pulmonary artery for repair of various complex congenital cardiac anomalies in 56 patients (aged 15 days to 33 years; median, 11 years). Forty-four patients had a total of 56 previous palliative procedures, which contributed to postoperative morbidity and mortality. Six patients had a total of seven episodes of early or late sepsis involving the conduit. One patient, treated for early sepsis, again developed infection in the Hancock graft 1 year postoperatively and died. Three other patients, 2 with calcified allografts, developed infections 4 months to 7 years following repair and required graft replacement. Hemodynamic data 1 month to 5 years (mean, 1.6 years) following repair revealed mild to moderate obstruction (less than 45 mm Hg gradient) at the Hancock conduit valve ring in 13 of 19 patients, while 5 had large pressure gradients (greater than 75 mm Hg). All aortic allografts had severe obstruction and calcification necessitating graft replacement. It is anticipated that improved technique and appropriate timing of palliative and corrective operations will substantially reduce or eliminate these problems.     

Circular esophagomyotomy of upper pouch in primary repair of long-segment esophageal atresia

A method of performing circular esophagomyotomy of the upper pouch is described as an effective technique for use in repair of esophageal atresia where the ends cannot be brought together.     

Growth after Surgical Repair of Simple d-Transposition of the Great Arteries

The effect of the Mustard procedure on growth was assessed in 45 patients with simple D-transposition of the great arteries (DTGA) surviving for at least one year after operation. Growth failure (below the third percentile for height, weight, or both) was found in 25 of the 45 patients preoperatively and in 8 patients postoperatively.The principal factors associated with poor growth before repair were advancing age, increased pulmonary and systemic flow, and subpulmonic stenosis. In those patients without postoperative growth failure, growth had returned to the normal range within two years. All patients with retarded growth after the Mustard procedure had had preoperative growth failure as well. In addition, all 8 patients with postoperative growth failure had one or more major residual hemodynamic abnormalities, whereas residual lesions were present in only 10 of the 37 patients with normal postoperative growth.     

Management of extensive doxorubicin hydrochloride extravasation injuries

Forty patients with extensive doxorubicin hydrochloride extravasation injuries are reviewed. These injuries were located in critical anatomic areas such as the palmar aspect of the wrist, dorsum of the hand, and antecubital fossa. Contributing factors were related to local venous pathology, the mode of administration, and the lack of recognition of extravasation. Treatment of these injuries consisted of extensive debridement of all involved tissue and delayed closure by a variety of techniques. The complications and morbidity secondary to doxorubicin hydrochloride extravasation are often more disabling than the patient's primary disease. The degree of disability is related to the site of extravasation, patient's age, and delay before surgical complication. Early recognition and excision and delayed closure yield the most successful results.     

Tetralogy of Fallot with a Single Pulmonary Artery: Operative Repair

Surgical repair was performed on 8 patients with tetralogy of Fallot and congenital or acquired absence of the left pulmonary artery. Prior palliative systemic-pulmonary artery shunts had been performed in the 5 patients with acquired absence of the pulmonary artery, and in none was repair of the damaged pulmonary artery possible. A valve-containing conduit (Hancock) was used in each patient to prevent pulmonary valvular regurgitation during the early postoperative period. All patients survived operation and have exhibited marked symptomatic and hemodynamic improvement. This contrasts with the poor results of corrective operation previously reported in patients in this diagnostic category. We believe that the present improved results are due in large part to the valved conduit, and we therefore recommend its use during repair in children or adults with tetralogy and a single pulmonary artery.